Piston type hydraulic pumps/motors of the type having a rotating barrel containing a plurality of pumping pistons are well known. An illustrative pump motor configuration is contained in U.S. Pat. No. 3,980,003. As described in that patent, hydrostatic balancing forces are developed at the interface of a fixed porting surface of a porting plate or end cap and rotating piston-containing barrel, to provide lubrication, but maintain fluid leakage sufficiently low to avoid a substantial negative effect on pumping efficiency. U.S. Pat. No. 2,298,850 teaches the use of hydraulic force pads similar to those employed in this invention but which are fed a constant but small amount of fluid to regulate the separation of the porting plate and rotating barrel over its full range of operation. When operating in a motor mode and the motor is at rest with no driving fluid being supplied, the barrel and port plate are in metal-to-metal contact. This establishes a coefficient of friction higher than that during normal operation giving the motor a poor starting torque characteristic. Starting torque is a critical design criterion which often determines the motor size for a certain load requirement. A pump larger than needed for normal running will often need to be selected to overcome start-up resistance. Additional hydrostatic separation liquid may be applied to eliminate this condition, but if such augmented hydrostatic separation forces are applied throughout the running regime, the motor will experience excessive leakage and a reduction in efficiency during normal running.